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root/jsr166/jsr166/src/jsr166y/ForkJoinTask.java

Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.85 by jsr166, Tue Jan 31 01:51:13 2012 UTC vs.
Revision 1.87 by dl, Sun Mar 4 15:52:45 2012 UTC

#	Line 137 | Line 137 | import java.lang.reflect.Constructor;
137		* {@link Phaser}, {@link #helpQuiesce}, and {@link #complete}) that
138		* may be of use in constructing custom subclasses for problems that
139		* are not statically structured as DAGs. To support such usages a
140	<	* ForkJoinTask may be atomically <em>marked</em> using {@link
141	<	* #markForkJoinTask} and checked for marking using {@link
142	<	* #isMarkedForkJoinTask}. The ForkJoinTask implementation does not
143	<	* use these {@code protected} methods or marks for any purpose, but
140	>	* ForkJoinTask may be atomically <em>tagged</em> with a {@code
141	>	* short} value using {@link #setForkJoinTaskTag} or {@link
142	>	* #compareAndSetForkJoinTaskTag} and checked using {@link
143	>	* #getForkJoinTaskTag}. The ForkJoinTask implementation does not
144	>	* use these {@code protected} methods or tags for any purpose, but
145		* they may be of use in the construction of specialized subclasses.
146		* For example, parallel graph traversals can use the supplied methods
147		* to avoid revisiting nodes/tasks that have already been processed.
148	<	* Also, completion based designs can use them to record that one
149	<	* subtask has completed. (Method names for marking are bulky in part
150	<	* to encourage definition of methods that reflect their usage
150	<	* patterns.)
148	>	* Also, completion based designs can use them to record that subtasks
149	>	* have completed. (Method names for tagging are bulky in part to
150	>	* encourage definition of methods that reflect their usage patterns.)
151		*
152		* <p>Most base support methods are {@code final}, to prevent
153		* overriding of implementations that are intrinsically tied to the
#	Line 197 | Line 197 | public abstract class ForkJoinTask<V> im
197		* methods in a way that flows well in javadocs.
198		*/
199
200	–	/**
201	–	* The number of times to try to help join a task without any
202	–	* apparent progress before giving up and blocking. The value is
203	–	* arbitrary but should be large enough to cope with transient
204	–	* stalls (due to GC etc) that can cause helping methods not to be
205	–	* able to proceed because other workers have not progressed to
206	–	* the point where subtasks can be found or taken.
207	–	*/
208	–	private static final int HELP_RETRIES = 32;
209	–
200		/*
201		* The status field holds run control status bits packed into a
202		* single int to minimize footprint and to ensure atomicity (via
203		* CAS).  Status is initially zero, and takes on nonnegative
204	<	* values until completed, upon which status holds value
205	<	* NORMAL, CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking
206	<	* waits by other threads have the SIGNAL bit set.  Completion of
207	<	* a stolen task with SIGNAL set awakens any waiters via
208	<	* notifyAll. Even though suboptimal for some purposes, we use
209	<	* basic builtin wait/notify to take advantage of "monitor
210	<	* inflation" in JVMs that we would otherwise need to emulate to
211	<	* avoid adding further per-task bookkeeping overhead.  We want
212	<	* these monitors to be "fat", i.e., not use biasing or thin-lock
213	<	* techniques, so use some odd coding idioms that tend to avoid
214	<	* them.
204	>	* values until completed, upon which status (anded with
205	>	* DONE_MASK) holds value NORMAL, CANCELLED, or EXCEPTIONAL. Tasks
206	>	* undergoing blocking waits by other threads have the SIGNAL bit
207	>	* set.  Completion of a stolen task with SIGNAL set awakens any
208	>	* waiters via notifyAll. Even though suboptimal for some
209	>	* purposes, we use basic builtin wait/notify to take advantage of
210	>	* "monitor inflation" in JVMs that we would otherwise need to
211	>	* emulate to avoid adding further per-task bookkeeping overhead.
212	>	* We want these monitors to be "fat", i.e., not use biasing or
213	>	* thin-lock techniques, so use some odd coding idioms that tend
214	>	* to avoid them, mainly by arranging that every synchronized
215	>	* block performs a wait, notifyAll or both.
216	>	*
217	>	* These control bits occupy only (some of) the upper half (16
218	>	* bits) of status field. The lower bits are used for user-defined
219	>	* tags.
220		*/
221
222		/** The run status of this task */
223		volatile int status; // accessed directly by pool and workers
224	<	static final int NORMAL      = 0xfffffffc;  // negative with low 2 bits 0
225	<	static final int CANCELLED   = 0xfffffff8;  // must be < NORMAL
226	<	static final int EXCEPTIONAL = 0xfffffff4;  // must be < CANCELLED
227	<	static final int SIGNAL      = 0x00000001;
228	<	static final int MARKED      = 0x00000002;
224	>	static final int DONE_MASK   = 0xf0000000;  // mask out non-completion bits
225	>	static final int NORMAL      = 0xf0000000;  // must be negative
226	>	static final int CANCELLED   = 0xc0000000;  // must be < NORMAL
227	>	static final int EXCEPTIONAL = 0x80000000;  // must be < CANCELLED
228	>	static final int SIGNAL      = 0x00010000;  // must be >= 1 << 16
229	>	static final int SMASK       = 0x0000ffff;  // short bits for tags
230
231		/**
232		* Marks completion and wakes up threads waiting to join this
233	<	* task, also clearing signal request bits. A specialization for
238	<	* NORMAL completion is in method doExec.
233	>	* task.
234		*
235		* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
236		* @return completion status on exit
#	Line 244 | Line 239 | public abstract class ForkJoinTask<V> im
239		for (int s;;) {
240		if ((s = status) < 0)
241		return s;
242	<	if (U.compareAndSwapInt(this, STATUS, s, (s & ~SIGNAL)|completion)) {
243	<	if ((s & SIGNAL) != 0)
242	>	if (U.compareAndSwapInt(this, STATUS, s, s | completion)) {
243	>	if ((s >>> 16) != 0)
244		synchronized (this) { notifyAll(); }
245		return completion;
246		}
#	Line 267 | Line 262 | public abstract class ForkJoinTask<V> im
262		} catch (Throwable rex) {
263		return setExceptionalCompletion(rex);
264		}
265	<	while ((s = status) >= 0 && completed) {
266	<	if (U.compareAndSwapInt(this, STATUS, s, (s & ~SIGNAL)|NORMAL)) {
272	<	if ((s & SIGNAL) != 0)
273	<	synchronized (this) { notifyAll(); }
274	<	return NORMAL;
275	<	}
276	<	}
265	>	if (completed)
266	>	s = setCompletion(NORMAL);
267		}
268		return s;
269		}
270
271		/**
272	+	* Tries to set SIGNAL status. Used by ForkJoinPool. Other
273	+	* variants are directly incorporated into externalAwaitDone etc.
274	+	*
275	+	* @return true if successful
276	+	*/
277	+	final boolean trySetSignal() {
278	+	int s;
279	+	return U.compareAndSwapInt(this, STATUS, s = status, s | SIGNAL);
280	+	}
281	+
282	+	/**
283		* Blocks a non-worker-thread until completion.
284		* @return status upon completion
285		*/
286		private int externalAwaitDone() {
287	+	boolean interrupted = false;
288		int s;
289	<	if ((s = status) >= 0) {
290	<	boolean interrupted = false;
291	<	synchronized (this) {
292	<	while ((s = status) >= 0) {
291	<	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
289	>	while ((s = status) >= 0) {
290	>	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
291	>	synchronized (this) {
292	>	if (status >= 0) {
293		try {
294		wait();
295		} catch (InterruptedException ie) {
296		interrupted = true;
297		}
298		}
299	+	else
300	+	notifyAll();
301		}
302		}
300	–	if (interrupted)
301	–	Thread.currentThread().interrupt();
303		}
304	+	if (interrupted)
305	+	Thread.currentThread().interrupt();
306		return s;
307		}
308
309		/**
310	<	* Blocks a non-worker-thread until completion or interruption or timeout.
310	>	* Blocks a non-worker-thread until completion or interruption.
311		*/
312	<	private int externalInterruptibleAwaitDone(long millis)
310	<	throws InterruptedException {
312	>	private int externalInterruptibleAwaitDone() throws InterruptedException {
313		int s;
314		if (Thread.interrupted())
315		throw new InterruptedException();
316	<	if ((s = status) >= 0) {
317	<	synchronized (this) {
318	<	while ((s = status) >= 0) {
319	<	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
320	<	wait(millis);
321	<	if (millis > 0L)
322	<	break;
321	<	}
316	>	while ((s = status) >= 0) {
317	>	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
318	>	synchronized (this) {
319	>	if (status >= 0)
320	>	wait();
321	>	else
322	>	notifyAll();
323		}
324		}
325		}
326		return s;
327		}
328
328	–
329		/**
330		* Implementation for join, get, quietlyJoin. Directly handles
331		* only cases of already-completed, external wait, and
332	<	* unfork+exec.  Others are relayed to awaitJoin.
332	>	* unfork+exec.  Others are relayed to ForkJoinPool.awaitJoin.
333		*
334		* @return status upon completion
335		*/
336		private int doJoin() {
337		int s; Thread t; ForkJoinWorkerThread wt; ForkJoinPool.WorkQueue w;
338		if ((s = status) >= 0) {
339	<	if (!((t = Thread.currentThread()) instanceof ForkJoinWorkerThread))
340	<	s = externalAwaitDone();
341	<	else if (!(w = (wt = (ForkJoinWorkerThread)t).workQueue).
342	<	tryUnpush(this) || (s = doExec()) >= 0)
343	<	s = awaitJoin(w, wt.pool);
344	<	}
345	<	return s;
346	<	}
347	<
348	<	/**
349	<	* Helps and/or blocks until joined.
350	<	*
351	<	* @param w the joiner
352	<	* @param p the pool
353	<	* @return status upon completion
354	<	*/
355	<	private int awaitJoin(ForkJoinPool.WorkQueue w, ForkJoinPool p) {
356	<	int s;
357	<	ForkJoinTask<?> prevJoin = w.currentJoin;
358	<	w.currentJoin = this;
359	<	for (int k = HELP_RETRIES; (s = status) >= 0;) {
360	<	if ((w.queueSize() > 0) ?
361	<	w.tryRemoveAndExec(this) :        // self-help
362	<	p.tryHelpStealer(w, this))        // help process tasks
363	<	k = HELP_RETRIES;                 // reset if made progress
364	<	else if ((s = status) < 0)            // recheck
365	<	break;
366	<	else if (--k > 0) {
367	<	if ((k & 3) == 1)
368	<	Thread.yield();               // occasionally yield
369	<	}
370	<	else if (k == 0)
371	<	p.tryPollForAndExec(w, this);     // uncommon self-help case
372	<	else if (p.tryCompensate()) {         // true if can block
373	<	try {
374	<	int ss = status;
375	<	if (ss >= 0 &&                // assert need signal
376	<	U.compareAndSwapInt(this, STATUS, ss, ss | SIGNAL)) {
377	<	synchronized (this) {
378	<	if (status >= 0)      // block
379	<	wait();
380	<	}
381	<	}
382	<	} catch (InterruptedException ignore) {
383	<	} finally {
384	<	p.incrementActiveCount();     // re-activate
385	<	}
339	>	if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) {
340	>	if (!(w = (wt = (ForkJoinWorkerThread)t).workQueue).
341	>	tryUnpush(this) || (s = doExec()) >= 0)
342	>	s = wt.pool.awaitJoin(w, this);
343		}
344	+	else
345	+	s = externalAwaitDone();
346		}
388	–	w.currentJoin = prevJoin;
347		return s;
348		}
349
#	Line 395 | Line 353 | public abstract class ForkJoinTask<V> im
353		* @return status upon completion
354		*/
355		private int doInvoke() {
356	<	int s; Thread t;
356	>	int s; Thread t; ForkJoinWorkerThread wt;
357		if ((s = doExec()) >= 0) {
358	<	if (!((t = Thread.currentThread()) instanceof ForkJoinWorkerThread))
358	>	if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)
359	>	s = (wt = (ForkJoinWorkerThread)t).pool.awaitJoin(wt.workQueue,
360	>	this);
361	>	else
362		s = externalAwaitDone();
402	–	else {
403	–	ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
404	–	s = awaitJoin(wt.workQueue, wt.pool);
405	–	}
363		}
364		return s;
365		}
#	Line 539 | Line 496 | public abstract class ForkJoinTask<V> im
496		* @return the exception, or null if none
497		*/
498		private Throwable getThrowableException() {
499	<	if (status != EXCEPTIONAL)
499	>	if ((status & DONE_MASK) != EXCEPTIONAL)
500		return null;
501		int h = System.identityHashCode(this);
502		ExceptionNode e;
#	Line 624 | Line 581 | public abstract class ForkJoinTask<V> im
581		}
582
583		/**
584	<	* Report the result of invoke or join; called only upon
628	<	* non-normal return of internal versions.
584	>	* Throws exception, if any, associated with the given status.
585		*/
586	<	private V reportResult() {
587	<	int s; Throwable ex;
588	<	if ((s = status) == CANCELLED)
589	<	throw new CancellationException();
590	<	if (s == EXCEPTIONAL && (ex = getThrowableException()) != null)
586	>	private void reportException(int s) {
587	>	Throwable ex = ((s == CANCELLED) ?  new CancellationException() :
588	>	(s == EXCEPTIONAL) ? getThrowableException() :
589	>	null);
590	>	if (ex != null)
591		U.throwException(ex);
636	–	return getRawResult();
592		}
593
594		// public methods
#	Line 657 | Line 612 | public abstract class ForkJoinTask<V> im
612		* @return {@code this}, to simplify usage
613		*/
614		public final ForkJoinTask<V> fork() {
615	<	ForkJoinWorkerThread wt;
661	<	(wt = (ForkJoinWorkerThread)Thread.currentThread()).
662	<	workQueue.push(this, wt.pool);
615	>	((ForkJoinWorkerThread)Thread.currentThread()).workQueue.push(this);
616		return this;
617		}
618
#	Line 675 | Line 628 | public abstract class ForkJoinTask<V> im
628		* @return the computed result
629		*/
630		public final V join() {
631	<	if (doJoin() != NORMAL)
632	<	return reportResult();
633	<	else
634	<	return getRawResult();
631	>	int s;
632	>	if ((s = doJoin() & DONE_MASK) != NORMAL)
633	>	reportException(s);
634	>	return getRawResult();
635		}
636
637		/**
#	Line 690 | Line 643 | public abstract class ForkJoinTask<V> im
643		* @return the computed result
644		*/
645		public final V invoke() {
646	<	if (doInvoke() != NORMAL)
647	<	return reportResult();
648	<	else
649	<	return getRawResult();
646	>	int s;
647	>	if ((s = doInvoke() & DONE_MASK) != NORMAL)
648	>	reportException(s);
649	>	return getRawResult();
650		}
651
652		/**
#	Line 720 | Line 673 | public abstract class ForkJoinTask<V> im
673		* @throws NullPointerException if any task is null
674		*/
675		public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) {
676	+	int s1, s2;
677		t2.fork();
678	<	t1.invoke();
679	<	t2.join();
678	>	if ((s1 = t1.doInvoke() & DONE_MASK) != NORMAL)
679	>	t1.reportException(s1);
680	>	if ((s2 = t2.doJoin() & DONE_MASK) != NORMAL)
681	>	t2.reportException(s2);
682		}
683
684		/**
#	Line 859 | Line 815 | public abstract class ForkJoinTask<V> im
815		* @return {@code true} if this task is now cancelled
816		*/
817		public boolean cancel(boolean mayInterruptIfRunning) {
818	<	return setCompletion(CANCELLED) == CANCELLED;
818	>	return (setCompletion(CANCELLED) & DONE_MASK) == CANCELLED;
819		}
820
821		public final boolean isDone() {
#	Line 867 | Line 823 | public abstract class ForkJoinTask<V> im
823		}
824
825		public final boolean isCancelled() {
826	<	return status == CANCELLED;
826	>	return (status & DONE_MASK) == CANCELLED;
827		}
828
829		/**
#	Line 887 | Line 843 | public abstract class ForkJoinTask<V> im
843		* exception and was not cancelled
844		*/
845		public final boolean isCompletedNormally() {
846	<	return status == NORMAL;
846	>	return (status & DONE_MASK) == NORMAL;
847		}
848
849		/**
#	Line 898 | Line 854 | public abstract class ForkJoinTask<V> im
854		* @return the exception, or {@code null} if none
855		*/
856		public final Throwable getException() {
857	<	int s = status;
857	>	int s = status & DONE_MASK;
858		return ((s >= NORMAL)    ? null :
859		(s == CANCELLED) ? new CancellationException() :
860		getThrowableException());
#	Line 948 | Line 904 | public abstract class ForkJoinTask<V> im
904		}
905
906		/**
907	+	* Completes this task. The most recent value established by
908	+	* {@link #setRawResult} (or {@code null}) will be returned as the
909	+	* result of subsequent invocations of {@code join} and related
910	+	* operations. This method may be useful when processing sets of
911	+	* tasks when some do not otherwise complete normally. Its use in
912	+	* other situations is discouraged.
913	+	*/
914	+	public final void quietlyComplete() {
915	+	setCompletion(NORMAL);
916	+	}
917	+
918	+	/**
919		* Waits if necessary for the computation to complete, and then
920		* retrieves its result.
921		*
#	Line 960 | Line 928 | public abstract class ForkJoinTask<V> im
928		*/
929		public final V get() throws InterruptedException, ExecutionException {
930		int s = (Thread.currentThread() instanceof ForkJoinWorkerThread) ?
931	<	doJoin() : externalInterruptibleAwaitDone(0L);
931	>	doJoin() : externalInterruptibleAwaitDone();
932		Throwable ex;
933	<	if (s == CANCELLED)
933	>	if ((s &= DONE_MASK) == CANCELLED)
934		throw new CancellationException();
935		if (s == EXCEPTIONAL && (ex = getThrowableException()) != null)
936		throw new ExecutionException(ex);
#	Line 985 | Line 953 | public abstract class ForkJoinTask<V> im
953		*/
954		public final V get(long timeout, TimeUnit unit)
955		throws InterruptedException, ExecutionException, TimeoutException {
956	<	// Messy in part because we measure in nanos, but wait in millis
957	<	int s; long millis, nanos;
958	<	Thread t = Thread.currentThread();
959	<	if (!(t instanceof ForkJoinWorkerThread)) {
960	<	if ((millis = unit.toMillis(timeout)) > 0L)
961	<	s = externalInterruptibleAwaitDone(millis);
962	<	else
963	<	s = status;
964	<	}
965	<	else if ((s = status) >= 0 && (nanos = unit.toNanos(timeout)) > 0L) {
966	<	long deadline = System.nanoTime() + nanos;
967	<	ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
968	<	ForkJoinPool.WorkQueue w = wt.workQueue;
969	<	ForkJoinPool p = wt.pool;
970	<	if (w.tryUnpush(this))
971	<	doExec();
972	<	boolean blocking = false;
956	>	if (Thread.interrupted())
957	>	throw new InterruptedException();
958	>	// Messy in part because we measure in nanosecs, but wait in millisecs
959	>	int s; long ns, ms;
960	>	if ((s = status) >= 0 && (ns = unit.toNanos(timeout)) > 0L) {
961	>	long deadline = System.nanoTime() + ns;
962	>	ForkJoinPool p = null;
963	>	ForkJoinPool.WorkQueue w = null;
964	>	Thread t = Thread.currentThread();
965	>	if (t instanceof ForkJoinWorkerThread) {
966	>	ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
967	>	p = wt.pool;
968	>	w = wt.workQueue;
969	>	s = p.helpJoinOnce(w, this); // no retries on failure
970	>	}
971	>	boolean canBlock = false;
972	>	boolean interrupted = false;
973		try {
974		while ((s = status) >= 0) {
975	<	if (w.runState < 0)
975	>	if (w != null && w.runState < 0)
976		cancelIgnoringExceptions(this);
977	<	else if (!blocking)
978	<	blocking = p.tryCompensate();
977	>	else if (!canBlock) {
978	>	if (p == null || p.tryCompensate(this, null))
979	>	canBlock = true;
980	>	}
981		else {
982	<	millis = TimeUnit.NANOSECONDS.toMillis(nanos);
1013	<	if (millis > 0L &&
982	>	if ((ms = TimeUnit.NANOSECONDS.toMillis(ns)) > 0L &&
983		U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
984	<	try {
985	<	synchronized (this) {
986	<	if (status >= 0)
987	<	wait(millis);
984	>	synchronized (this) {
985	>	if (status >= 0) {
986	>	try {
987	>	wait(ms);
988	>	} catch (InterruptedException ie) {
989	>	if (p == null)
990	>	interrupted = true;
991	>	}
992		}
993	<	} catch (InterruptedException ie) {
993	>	else
994	>	notifyAll();
995		}
996		}
997	<	if ((s = status) < 0 ||
998	<	(nanos = deadline - System.nanoTime()) <= 0L)
997	>	if ((s = status) < 0 || interrupted ||
998	>	(ns = deadline - System.nanoTime()) <= 0L)
999		break;
1000		}
1001		}
1002		} finally {
1003	<	if (blocking)
1003	>	if (p != null && canBlock)
1004		p.incrementActiveCount();
1005		}
1006	+	if (interrupted)
1007	+	throw new InterruptedException();
1008		}
1009	<	if (s != NORMAL) {
1009	>	if ((s &= DONE_MASK) != NORMAL) {
1010		Throwable ex;
1011		if (s == CANCELLED)
1012		throw new CancellationException();
#	Line 1097 | Line 1073 | public abstract class ForkJoinTask<V> im
1073		* setRawResult(null)}.
1074		*/
1075		public void reinitialize() {
1076	<	if (status == EXCEPTIONAL)
1076	>	if ((status & DONE_MASK) == EXCEPTIONAL)
1077		clearExceptionalCompletion();
1078		else
1079		status = 0;
#	Line 1335 | Line 1311 | public abstract class ForkJoinTask<V> im
1311		return wt.pool.nextTaskFor(wt.workQueue);
1312		}
1313
1314	<	// Mark-bit operations
1314	>	// tag operations
1315
1316		/**
1317	<	* Returns true if this task is marked.
1317	>	* Returns the tag for this task.
1318		*
1319	<	* @return true if this task is marked
1319	>	* @return the tag for this task
1320		* @since 1.8
1321		*/
1322	<	public final boolean isMarkedForkJoinTask() {
1323	<	return (status & MARKED) != 0;
1322	>	public final short getForkJoinTaskTag() {
1323	>	return (short)status;
1324		}
1325
1326		/**
1327	<	* Atomically sets the mark on this task.
1327	>	* Atomically sets the tag value for this task.
1328		*
1329	<	* @return true if this task was previously unmarked
1329	>	* @param tag the tag value
1330	>	* @return the previous value of the tag
1331		* @since 1.8
1332		*/
1333	<	public final boolean markForkJoinTask() {
1333	>	public final short setForkJoinTaskTag(short tag) {
1334		for (int s;;) {
1335	<	if (((s = status) & MARKED) != 0)
1336	<	return false;
1337	<	if (U.compareAndSwapInt(this, STATUS, s, s | MARKED))
1361	<	return true;
1335	>	if (U.compareAndSwapInt(this, STATUS, s = status,
1336	>	(s & ~SMASK) | (tag & SMASK)))
1337	>	return (short)s;
1338		}
1339		}
1340
1341		/**
1342	<	* Atomically clears the mark on this task.
1342	>	* Atomically conditionally sets the tag value for this task.
1343	>	* Among other applications, tags can be used as visit markers
1344	>	* in tasks operating on graphs, as in mathods that check: {@code
1345	>	* if (task.compareAndSetForkJoinTaskTag((short)0, (short)1))}
1346	>	* before processing, otherwise exiting because the node has
1347	>	* already been visited.
1348		*
1349	<	* @return true if this task was previously marked
1349	>	* @param e the expected tag value
1350	>	* @param tag the new tag value
1351	>	* @return true if successful; i.e., the current value was
1352	>	* equal to e and is now tag.
1353		* @since 1.8
1354		*/
1355	<	public final boolean unmarkForkJoinTask() {
1355	>	public final boolean compareAndSetForkJoinTaskTag(short e, short tag) {
1356		for (int s;;) {
1357	<	if (((s = status) & MARKED) == 0)
1357	>	if ((short)(s = status) != e)
1358		return false;
1359	<	if (U.compareAndSwapInt(this, STATUS, s, s & ~MARKED))
1359	>	if (U.compareAndSwapInt(this, STATUS, s,
1360	>	(s & ~SMASK) | (tag & SMASK)))
1361		return true;
1362		}
1363		}
#	Line 1385 | Line 1370 | public abstract class ForkJoinTask<V> im
1370		static final class AdaptedRunnable<T> extends ForkJoinTask<T>
1371		implements RunnableFuture<T> {
1372		final Runnable runnable;
1388	–	final T resultOnCompletion;
1373		T result;
1374		AdaptedRunnable(Runnable runnable, T result) {
1375		if (runnable == null) throw new NullPointerException();
1376		this.runnable = runnable;
1377	<	this.resultOnCompletion = result;
1377	>	this.result = result; // OK to set this even before completion
1378		}
1379	<	public T getRawResult() { return result; }
1380	<	public void setRawResult(T v) { result = v; }
1381	<	public boolean exec() {
1382	<	runnable.run();
1383	<	result = resultOnCompletion;
1384	<	return true;
1379	>	public final T getRawResult() { return result; }
1380	>	public final void setRawResult(T v) { result = v; }
1381	>	public final boolean exec() { runnable.run(); return true; }
1382	>	public final void run() { invoke(); }
1383	>	private static final long serialVersionUID = 5232453952276885070L;
1384	>	}
1385	>
1386	>	/**
1387	>	* Adaptor for Runnables without results
1388	>	*/
1389	>	static final class AdaptedRunnableAction extends ForkJoinTask<Void>
1390	>	implements RunnableFuture<Void> {
1391	>	final Runnable runnable;
1392	>	AdaptedRunnableAction(Runnable runnable) {
1393	>	if (runnable == null) throw new NullPointerException();
1394	>	this.runnable = runnable;
1395		}
1396	<	public void run() { invoke(); }
1396	>	public final Void getRawResult() { return null; }
1397	>	public final void setRawResult(Void v) { }
1398	>	public final boolean exec() { runnable.run(); return true; }
1399	>	public final void run() { invoke(); }
1400		private static final long serialVersionUID = 5232453952276885070L;
1401		}
1402
#	Line 1414 | Line 1411 | public abstract class ForkJoinTask<V> im
1411		if (callable == null) throw new NullPointerException();
1412		this.callable = callable;
1413		}
1414	<	public T getRawResult() { return result; }
1415	<	public void setRawResult(T v) { result = v; }
1416	<	public boolean exec() {
1414	>	public final T getRawResult() { return result; }
1415	>	public final void setRawResult(T v) { result = v; }
1416	>	public final boolean exec() {
1417		try {
1418		result = callable.call();
1419		return true;
#	Line 1428 | Line 1425 | public abstract class ForkJoinTask<V> im
1425		throw new RuntimeException(ex);
1426		}
1427		}
1428	<	public void run() { invoke(); }
1428	>	public final void run() { invoke(); }
1429		private static final long serialVersionUID = 2838392045355241008L;
1430		}
1431
#	Line 1441 | Line 1438 | public abstract class ForkJoinTask<V> im
1438		* @return the task
1439		*/
1440		public static ForkJoinTask<?> adapt(Runnable runnable) {
1441	<	return new AdaptedRunnable<Void>(runnable, null);
1441	>	return new AdaptedRunnableAction(runnable);
1442		}
1443
1444		/**

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